It is well recognized in the petroleum industry that boron containing compounds are desirable additives for for lubricating oils. One such boron containing compound is disclosed in U.S. Pat. No. 3,224,971 to Knowles et al. which relates to intracomplexed borate esters and to lubricating compositions containing said esters. The borate esters are organo-boron compounds derived from boric acid and a bis(o-hydroxy-alkylphenyl)amine or sulfide.
Another extreme pressure lubrication composition is disclosed in U.S. Pat. No. 3,185,644 to Knowles et al., which relates to lubricating compositions containing amine salts of boron-containing compounds. The amine salts are formed by reaction of a hydroxy substituted amine and a trihydrocarbyl borate. The amine-borate compounds thus formed are described as useful as load carrying additives for mineral and synthetic base lubricating oils.
Boric-acid-alkylolamine reaction products and lubricating oils containing the same are disclosed in U.S. Pat. No. 3,227,739 to Versteeg. These amine type products are prepared by reacting equal molar proportions of diethanolamine or dipropanolamine and a long chain, 1,2-epoxide. The intermediate reaction product thus produced is reacted with boric acid to produce the final reaction product. These compounds are added to lubricants to prevent rust formation.
Another boron ester composition is described in U.S. Pat. No. 3,269,853 to English et al. which discloses a boron ester curing agent which consists of a cyclic ring structure containing boron, oxygen, nitrogen, carbon and hydrogen.
Another boron composition is disclosed in U.S. Pat. No. 3,598,855 to Cyba which relates to cyclic borates of polymeric alkanolamines formed by reacting a borylating agent with a polymeric alkanolamine. The compounds thus formed are described as additives for a wide variety of petroleum products including lubricating oils.
Currently, there are phosphorus-containing additives which provide extreme pressure, anti-wear and/or friction-reducing properties to automotive engine oils. However, with the advent of the catalytic converter, alternative additives are needed. During combustion in an automotive engine, any oil which leaks or seeps into the combustion chamber yields phosphorus deposits which poison the catalyst in the catalytic converter. As a result, there is a need for automotive engine oil additives which are phosphorus-free but provide useful extreme pressure, anti-wear, and/or friction-reducing properties to the oil.
Accordingly, it is one object of the invention to provide a phosphorus-free additive having such properties and which, upon combustion, will not adversely affect the catalyst in the automotive catalytic converter.
It is yet another object of the present invention to provide boron-containing, heterocyclic compounds or derivatives thereof which have extreme pressure, anti-wear and friction-reducing properties.
Yet another object of the present invention is to provide a lubricating composition having extreme pressure, anti-wear and friction-reducing properties.
A further object of the present invention is to provide a lubricating composition containing extreme pressure, anti-wear, friction-reducing and corrosion prevention additives, and in addition, an anti-oxidant to prevent attack of oxidants upon metal bearings.
Other objects and advantages of the invention will be apparent from the following description.